Pg. 33-39 Review questions 14-18
14 a. Neglecting air resistance, if you throw a baseball at 20 m/s to your friend who is on first base, will the catching speed be greater than, equal to, or less than 20 m/s? (3.5); b. does the speed change if air resistance is a factor? A. Equal to 20m/s.
B. Yes, it decreases. 15. What do we call a projectile that continually “falls” around Earth? An Earth Satellite. 16. How fast must a projectile moving horizontally travel so that the curve it follows matches the curve of Earth? If it is close to Earth then it is around 8km/s. 17. Why is it important that such a satellite be above Earth’s atmosphere? It is important because it avoids the heating effects of atmospheric friction. 18. What force acts on a satellite that is above Earth’s atmosphere? The only force is gravity. Plug and Chug 1-5
1. Calculate the resultant velocity of an airplane that normally flies at 200 km/h if it encounters a 50 km/h tailwind. If it encounters a 50 km/h headwind? 200+50=250km/h
2. Calculate the resultant of the pair of velocities 100km/h north and 75 km/h south. Calculate the resultant if both of the velocities are directed north. 100+75=175km/h
3. Calculate the magnitude of the resultant of a pair of 100 km/h velocity vectors that are at right angles to each other. 141km/h at 45 degrees
4. Calculate the magnitude of the horizontal and vertical components of a vector that is 100 units long and is oriented at 45 degrees. X=70.7 for horizontal and vertical components.
5. Calculate the resultant of a horizontal vector with a magnitude of 4 units and a vertical vector with magnitude of 3 units. How does the resultant compare with the hypotenuse of a right triangle having sides of 3 and 4 units? The resultant is 5, it is a 3, 4, 5 right triangle.
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